Make-ready of impression-cylinders of printing-presses.



A. W. COCHRAN III F. M. YOUNGS. MAKE READY DF IMPRESSION CYLINDERS 0FPRINTING PRESSES.

APPLICATION FILED AUG-7,1916.

Patented May 22, 1917.

a city of- Portland, county of Multnomah, State of Oregon, have inventeda certain' sn'e Rana one.

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nr-nnanr .or narnnssron-crnmnnns or rnrnrrne-rnnssns.

Specification of Letters Patent.

neeaaaa To all whom it may concern."

Be it known that we, ALBERT W. CoonRAN and FRED M. YoUNos, citizens ofthe United States, and residents, respectively, of the new and usefulImprovement in Make Ready of Impression-Cylinders of Printin Presses, ofwhich the following is a specii ication. I

@ur invention particularly relates to newspaper presses and has for itsobject the providing of impression cylinders with a make ready orcircumferential covering which will produce clear-cut imprints, andwhichyfurthermore, iseconomical with regard to its cost, application andlength of service.

In order to understand the nature of our invention, it is convenient tostate, in the first place the undesirable conditions now met with 1n theart, and contrasting therewith the beneficial results obtained from 7our improvement. In so doing reference will be had to the in which:

Figure 1 shows-diagrammatically an enlargedperspective elevation of thecapital letter T in block type; Fig. 2 shows a cross-section ofsuchtype, and apartial, longitudinal section of the accompanying drawings,

I impression cylinder provided with an imcyhnder perfect make ready 5and this figure repre-' sents in'exaggerated form the undesirableprinting action likely to result;

Fig. 2* shows diagrammatically the blurred imprint produced bysaidimproper condition;

Fig. 3 shows adiagrammatic, partial perspective, partly in section, ofan impression having. ourimproved make ready or circumferential coveringapplied thereto; Fig. t shows a manner of preparing our improved makeready for being fastened on the circumference of thecylinder;

Fig. 5 is an-exaggerated cross-section of oursaid make ready Fig. 6illustrates diagrammatically, and comparatively to-Fig. 2, the improvedre sults in the printing operation obtained by our invention; and

Fig 6 represents a clear-cut iniprint, to"

purpose of our inven- Patented May 22, 1911?. 1 Application filed August7, 1916. Serial No. 113,676.

sioncylinder must be made ready, and to I this end is circumferentiallycovered with a carries the stereotype .plate.

The two cylinders must have the same relative Working diameter, in orderto run at the same speed, for if they run at unequal speed therewould-be a tendency to drag the plate, relatively, over the papersupported by the impression cylinder, and so blur the imprint.

The make ready of the impression cylinder, as'heretofore practised,consisted in covering its circumference with a rubber blanket and'thencovering the latter with a felt blanket. The difliculty experienced insuch make ready is, the felt blanket permits considerable. sinking in,which must be guessed at, because allowance must be made in adjustingthe working diameters of the two cylinders; referring to those diameterswhich the cylinders respectively assume when the one carries the plateand the other the make ready. The necessity for figuringoutapproximately the allowance to be made for-the sinking in during theprinting operation is shown, for instance, in newspaper work, where halftones are printed alongside of type. In such case, since the half tonesrequire a heavier impression than the type, they must frequently besacrificed in order to have a sufliciently light impression which willnot paper printed to be pressed against the side faces of the type, thuscausing a distorted,

instead of atrue, clear-cut impression.

This undesirable efi'ect may be graphically illustrated by the aid ofthe diagrammatic Figs. 1, 2, 2? in the accompanying drawings.

Fig. 1 represents a diagrammatic perspective of a type printing thecapital letter T. Fig. 2 is a cross-section illustrating a likelyundesirable contact of the sheet imprinted with the side faces of thetype, due

we I

trated in Fig. 2*,

the character, as illustrated byto the fact that the make ready permits.

the type to sink too deeply into the surface.

. lln other words, under such conditions, the

speed so resulting would have a tendency to pull the paper so hard as tocause it to paper would have tearg and in that case the torn end of thea tendency to wind up on the impression cylinder so tightly as to killthe resiliency of the felt'blanket and render it unfit for furtherservice, because felt possesses only a limited come back property, forits texture is susceptible of being matted down by sustalned pressure;and in consequence of this inherent weak- I ness in felt the blanketusually employed 1 as a part of the make ready loses its come back evenin ordinary work in a comparatively short period. Then there is thisfurther disadvantage in the old style of make ready The felt blanketwill stretch, and has to be retightened from time to time, and in thisway it is finally stretched so thin as to lose its resiliency. At thesame time the diameter of the impression cylinder would be varied tosuch extend as to require it to be built up anew, in order to make itsworking diameter approximately equal to that of the printing cylinder,and prevent the consequences due to the working diameters of the twocylinders being unequal.

In seeking a remedy for said undesirable eflects we have discovered an'improved make ready for the lmpresslon cylinder,

which provides the latter with a suitable covering sutficientlyresilient to allow for the irregularities in the printing faces of'thestereotype plate, at the same time resisting the forming of any hollowsinto which the printing character maysink, and cause the undesirableconsequences illustrated by Figs 2, 2

The make ready invented by us consists of a base made of textile fabriccoated with a thin layer of composition 1, consisting of ground cork andoxidized linseed oil. In making up this composition the linseed oil isdried and ground up, then the two articles are mixed, and then the massis heated, and

' v while still hot the composition is spread 1n the form of a layer onthe textile base, and then rolled to the required uniform thickness,approximately .145 of an inch. This is the usual thickness of a built-upmake Figs. 6, 6.

manner ready, and it is to be noted that our make ready is to be used byitself, without any additional strips, felt blanket or rubber sheet, asheretofore required. Both and either of which possesses undesirableproperties from which we get away by our invention, as'mentioned. Inother words, our

new result can only be obtained by printing directly upon the surface ofour make ready, the lntervening draw sheet not belng considered as itmerely serves to keep our make ready in place on the cylinder, and

9 provided for that purpose on the channel z" of the impressioncylinder.

lin Fig. 3, 2' represents the impression cylinder, j the make readyorcovering as a whole. The impression cylinder is provided with theusual reels m, m, on the former of which one end of the draw sheet n isfastened, the other end being fastened on the reel m. The draw-sheetencircling the make ready is covered, the latter being flexed around thecylinder, and by then winding up the reels m, m, or one thereof, thedraw-sheet is drawn tautly, and in so doing firmly holds the make readyon the circumferential surface of the impression cylinder.

Ground cork is especially adapted for making our make ready since it has.the required resiliency for yielding to irregularities in the printingfaces, and a make ready made as herein described has, furthermore, thestable come back required to maintain the impression surface in auniform plane and also to resist the forming of cavities therein, forwhile resilient it is not so yielding as to permit crushing in, as doesfelt or rubber. Our improved make ready is particularly adapted forstereotype plates, which cannot be cast accurately, but

present a more or less irregular printing face.

The efiect obtained by my improved make. ready is graphicallyillustrated in Assuming the capital letter T is being printed, the makeready y will yield suficiently to allow for irregularities and produce aclear-cut imprint, such as is illustrated by Fig. 6 in comparison withFig. 2; for the type cannot sink into the surface of the make ready tosuch extent as to cause the portions y" of the make ready to bring thesheet imprinted into contact with the vertical edges 6', and thusprevents blurs as e, e in Fig. 2.

Our invention also produces a cheaper make ready, for the felt blanketmust be made throughout of a good quality of wool, in order that it,will have the necessary resiliency or come-back. And ourinvention hasthe further advantage that it requires less adjustment. In practice,with the old style of make ready, after the press had been run for atime it necessitated readjustment of the make ready. On the other hand,when our make ready is used, and has been adjusted after a days run, itwill stand. up indefinitely without further adjustment. In trialsheretofore made by us, our improved make ready has been used forsixmillion impressions and is still in good condition, While the oldstyle of make ready, using a felt blanket, would be about used up insuch work, and require renewal.

Our make ready is to be used in place of both the rubber blanket and thefelt blanket now in use.

We claim:

1. A make ready for impression cylinders consisting ofa strip ofsubstantial thickness made wholly of comminuted material havingresilient properties similar to cork, held in mass by a suitable bindingagent, and including other material adapted to "hold the mass againstpulling apart, said make ready being made of a thickness adapted forimprinting directly thereon.

2. A make ready for impression cylinders consisting of a strip ofsubstantial thickness made Wholly of comminuted material havingresilient properties similar to cork, held in mass by a suitable bindingagent, and mounted on a base strip adapted i to hold themass againstpulling apart, said make ready beingmade of a thickness adapted forimprinting directly thereon.

3. A make ready for impression cylin- ,ders consisting of a strip ofsubstantial thickness made wholly of comminuted cork held in, mass by asuitable binding agent, and mounted on a base strip adapted tohold themass against pulling apart, said make ready being made of a thicknessfor imprinting directly thereon.

4:. The combination with an impression cylinder, of a make readyconsisting of a circumferential coating of substantial thickness madewholly of comminuted cork and strip adapted to hold the mass againstpull-,

ing apart, and a draw sheet holding said strip flexed about thecylinder, said make ready being made of a thickness adapted I forimpressing directly thereon.

ALBERT W. COCHRAN. FRED M. YOUNGS.

